ReSharper 2017.1 Help

Keymap:

Duplicate Line or Selection

ReSharper | Edit | Duplicate TextCtrl+DReSharper_DuplicateText

One of the ways of creating a code element similar to an existing one (e.g. a nwe method overload, a new auto-implemented property) is cloning the existing element with copy-paste and then editing the clone.

ReSharper helps you streamline the cloning part - with a single keystroke (Ctrl+D) the cloned code is inserted right after the original.

To quickly duplicate the current line or selection

If you want to clone a line, set the caret at this line line. To clone an arbitrary piece of code, select it in the editor.